The biggest ever science expedition to the Arctic encountered extremely thin sea ice, which could threaten future efforts to study the region.
A team on board the Polarstern icebreaker ship聽began drifting last September until their vessel became locked in an ice floe. In the area off the Russian continental shelf where they started their journey, the ice was exceptionally thin compared with what models had predicted for the past two decades. The ice was around 50 centimetres thick, while it had been around 150 to 160 centimetres thick in three years of observations in the 1990s.
鈥淚t was something we were expecting, that it was quite thin. However, that it was so thin and so weathered was surprising. We found 40 to 50 centimetres of ice, but only half of it was frozen solid,鈥� says team member Thomas Krumpen at the Alfred Wegener Institute in Bremerhaven, Germany. The cause was last year鈥檚 unusually warm summer, he says.
Advertisement
Climate change has warmed the Arctic faster than the rest of the globe, and the team hopes to unravel the area鈥檚 secrets in winter, when it has been little-studied. The question of how quickly sea ice is disappearing has major consequences for the global climate and the region鈥檚 unique wildlife, including polar bears.
The fragility of the ice posed some logistical headaches for the 90 people aboard the icebreaker. It was so thin that an original plan to transport heavy gear across the ice to the Polarstern from another vessel had to be rethought. 鈥淭his was completely unexpected,鈥� says Krumpen. If such conditions are the new normal for the area, it will make follow-up missions increasingly difficult, warn Krumpen and his colleagues.
The researchers were also surprised by the ice floe they were locked in. Analysis found a lot of pebbles and other sediment in the ice, suggesting it formed in shallow seas around the Siberian coast. Rising temperatures mean that today it is relatively rare for such sea ice 鈥� which can also carry methane and nutrients 鈥� to make it as far as the central Arctic ocean.
The Cryosphere
Sign up to our free Fix the Planet newsletter to get a monthly dose of climate optimism delivered straight to your inbox
